Flocculation is the aggregation of particles of a colloidal suspension to form larger particles caused by random collisions between the suspended particles. In time, large enough particles are formed such that they will separate out due by gravity. Colloidal suspensions often have a long life due to repulsion between like charges, which keeps the particles from aggregating. Flocculation can be induced by the addition of a flocculating agent, for example an electrolyte, that essentially neutralizes the charged particles so that, subsequently, aggregation may occur. Flocculation is a well-known process in the treatment of sewage sludge and in the treatment of waste water in various industries such as the pulp and paper industry.